西瓜蔓枯病(Stagonosporopsis cucurbitacearum)产孢及接种方法比较

Comparison of Spore Production and Inoculation Methods of Watermelon Stem Blight

为了明确西瓜蔓枯病(Stagonosporopsis cucurbitacearum)的最佳产孢方法和最佳接种方法,为西瓜蔓枯病抗病种质资源的筛选与鉴定奠定坚实基础,围绕西瓜蔓枯病的产孢及接种方法展开研究。从蔓枯病分生孢子的产孢时间、产孢量、孢子形态等方面比较2种常见的产孢方法,发现紫外诱导产孢法与黄瓜诱导产孢法相比产孢时间短、产孢量多且稳定、孢子形态正常、成本低,是目前西瓜蔓枯病的最佳产孢方法。分别用离体菌饼接种法、活体孢子悬浮液点接法、活体孢子悬浮液喷雾接种法接种西瓜抗感材料,从操作难易程度、准确性等方面对3种接种方法进行了比较,发现3种接种方法各有优劣。离体菌饼接种法和活体孢子悬浮液点接法接种后,西瓜抗感材料抗感差异明显,而活体孢子悬浮液喷雾接种法接种后有感病材料表现为中抗。通过比较发现,离体菌饼接种法和活体孢子悬浮液点接法较为可靠,但离体菌饼接种法病情分级标准划分不够精细,材料间抗性的微小差别难以体现;活体孢子悬浮液点接法准确性较高,但操作复杂,耗时耗力;活体孢子悬浮液喷雾接种法操作简单,但难以准确控制接种体的量,准确性一般。因此建议大批量材料进行蔓枯病抗性鉴定时可采用活体孢子悬浮液喷雾接种法进行初步筛选,少量材料进行蔓枯病抗性鉴定时可采用活体孢子悬浮液点接法,离体菌饼接种法可作为辅助方法进一步验证接种结果。

In order to clarify the optimal spore production and inoculation methods for watermelon stem blight(Stagonosporosis cucurbitaceae),and to lay a solid foundation for the screening and identification of watermelon stem blight resistant germplasm resources,this article focuses on the spore production and inoculation methods of watermelon stem blight.Two common spore production methods were compared from the aspects of spore production time,spore yield,and spore morphology of stem blight.It was found that the UV induced spore production method had shorter spore production time,more stable spore yield,normal spore morphology,and lower cost compared to the cucumber induced spore production method.Currently,it was the best spore production method for watermelon stem blight.Watermelon resistant and susceptible materials were also inoculated with the methods of inoculum cake in vitro,spot inoculation with live spore suspension,and spray inoculation with live spore suspension,respectively.The three inoculation methods were compared in terms of operation difficulty and accuracy,and it was found that each of the three inoculation methods had advantages and disadvantages.The difference of resistance and susceptibility of watermelon resistant and susceptible materials was obvious after inoculating in vitro with cake inoculation and in vivo spore suspension spot inoculation,while the susceptible materials showed moderate resistance after inoculating in vivo spore suspension spray inoculation.Through comparison,it was found that the in vitro bacterial cake inoculation method and the live spore suspension point grafting method were more reliable,but the disease grading standards of the in vitro bacterial cake inoculation method were not precise enough,and the small differences in resistance between materials were difficult to reflect;the live spore suspension point grafting method had high accuracy,but the operation was complex,time-consuming,and labor-intensive;in vivo spore suspension spray inoculation method was simple in operation,but it was difficult to accurately control the amount of inoculum,and the accuracy was general.Therefore,it was suggested that the live spore suspension spray inoculation method could be used for preliminary screening when identifying the resistance of large quantities of materials to Fusarium wilt,and the live spore suspension spot connection method could be used when identifying the resistance of a small number of materials to Fusarium wilt,and the isolated cake inoculation method could be used as an auxiliary method to further verify the inoculation results.